Readme: updated info about debug env

README.md

@@ -59,10 +59,9 @@ Make commands:
 #### The main config loaded by `app/common.py`:
  - `templates_dir`, `static_dir` contain the paths
  to templates and static files directories correspondingly
- - `debug_env` is a path to `.env_debug`
- - `is_debug` is True when DEBUG env variable is set,
- and then `.env_debug` is loaded automatically
  - `settings` (pydantic.BaseSettings):
+    - `debug` means the application is running
+    in a development environment
     - `session_key`, `csrf_key` are secret keys
     for WTForms CSRF protection;  
     generated with secrets.token_urlsafe